Flip-chip bonding is commonly implemented by conventional micro-chip (such as RFID tag, diodes, transistors, LED etc.) packaging equipment. The device needs to use a robot arm to grab chips, then reverse the arm to make the chip bonding point toward the bonding substrate, then identify the alignment position and control the robotic arm movement aspect, and make a chip and substrate to connect accurately. Because the equipment needs robotic arm and the corresponding control devices, it is very expensive. It also needs to identify, control and grab one chip in one time, so the efficiency is very low.
ALIEN uses conventional FSA (Fluidic Self Assembly) technology to achieve chip and substrate self-alignment, but the method requires the substrate to form openings, the chip shape and size is critical for some applications. Such as RFID tags, the antenna substrate is very thin, so the FSA technology is very difficult and expensive to implement.